TDM Indications ('why do it'): Drug assays are costly, so the reason for monitoring and the additional information to be gained (if any) should be carefully considered. For some drugs, therapeutic drug monitoring helps to increase efficacy (vancomycin), to decrease toxicity (paracetamol) and to assist diagnosis (salicylates). Routine monitoring is not advocated for most drugs. The appropriate indications for therapeutic drug monitoring (and examples) include:  toxicity  - diagnosing toxicity when the clinical syndrome is undifferentiated (unexplained nausea in a patient taking digoxin) . avoiding toxicity (aminoglycosides, cyclosporin) Only clinically meaningful tests should be performed  dosing  - after dose adjustment (usually after reaching a steady state)  - assessment of adequate loading dose (after starting phenytoin treatment) - dose forecasting to help predict a patient's dose requirements1 (aminoglycosides)  monitoring  - assessing compliance (anticonvulsant concentrations in patients having frequent seizures)  - diagnosing under treatment (particularly important for prophylactic drugs such as anticonvulsants, immunosuppressants) - diagnosing failed therapy (therapeutic drug monitoring can help distinguish between ineffective drug treatment, non-compliance and adverse effects that mimic the underlying disease). The target concentration may depend on the indication. For example, the recommended concentration for digoxin depends on whether it is being used to treat atrial fibrillation or congestive heart failure. an experimentally determined relationship between plasma drug concentration and the pharmacological effect. • Knowledge of the drug level influences management.

1. V.G. Chandra lekha
Pharm-D
5th year

2.  Drug assays are costly, so the reason for monitoring and the
additional information to be gained (if any) should be carefully
considered.
 For some drugs, therapeutic drug monitoring helps to increase
efficacy (vancomycin), to decrease toxicity (paracetamol) and
to assist diagnosis (salicylates).
 Routine monitoring is not advocated for most drugs. Only
clinically meaningful tests should be performed.

3. The appropriate indications for therapeutic drug monitoring (and
examples) include:
Toxicity
Diagnosing toxicity when the clinical syndrome is undifferentiated
(unexplained nausea in a patient taking digoxin)
Avoiding toxicity (aminoglycosides, cyclosporin)

4. Dosing
After dose adjustment (usually after reaching a steady state)
Assessment of adequate loading dose (after starting phenytoin
treatment)
Dose forecasting to help predict a patient's dose requirements
(aminoglycosides)

5. Monitoring
Assessing compliance (anticonvulsant concentrations in
patients having frequent seizures)
Diagnosing under treatment (particularly important for
prophylactic drugs such as anticonvulsants, immuno-
suppressants)

6. Diagnosing failed therapy (therapeutic drug monitoring can
help distinguish between ineffective drug treatment, non-
compliance and adverse effects that mimic the underlying
disease).
An experimentally determined relationship between plasma
drug concentration and the pharmacological effect.
Knowledge of the drug level influences management

7. THANK U